1. Field of the Invention
The invention pertains to a scrubber and to a method for cleaning gases according to the subject invention.
2. Description of the Prior Art
Conventional scrubbers for cleaning gases that contain particulate and/or gaseous impurities normally comprise so-called absorption columns with packings or contact bodies that are sprayed with a washing fluid. In these absorption columns, an intimate contact is produced between the washing fluid and the gases. This leads to a highly efficient absorption of the gaseous impurities. The washing fluid may consist of water such that only an absorption takes place; however, the washing fluid may also contain reactants that convert the gaseous impurities, for example, hydrogen sulfide, sulfur dioxide, nitrogen oxides or ammonia, into environmentally compatible substances. These absorption columns are usually equipped with ordered or unordered packings that are arranged in individual sections on support grates. Fluid distributors are arranged on the head section of these columns in order to ensure a uniform spraying with the washing fluid. These fluid distributors may be realized in the form of gravity distributors or nozzle-type distributors.
The disadvantage of such columns lie in relatively high packing heights that result in significant pressure losses. If dust particles are present in the gas flow, the columns can only be operated with high maintenance costs because the packings would otherwise become clogged after a short operating time and the pressure loss would become excessively high.
The cleaning of gases without a gas pressure loss cannot, in principle, be realized because the required high mass transfer coefficients can only be achieved at high relative speeds between the gas and the washing fluid. When using liquid jet pumps, a pressure loss does not occur and adequate mass transfer coefficients are achieved. However, these pumps are not suitable for cleaning gases because the dwell time of the gas in the washing fluid is not sufficient for realizing an adequate absorption. An elongation of the jet pump does not improve these circumstances because large fluid drops are formed and the relative speed between the gas and the fluid simultaneously drops. Both effects are disadvantageous with respect to the absorption efficiency.